Germany’s largest bank might have failed to admit up to $12 billion of unrealized losses during the financial crisis, as stated in a complaint filed by three former Deutsche Bank employees to the US securities regulators.

­The complaint claims that Deutsche Bank hid $12 billion in losses on credit derivatives during the 2008-2009 crisis, the Financial Times reports on Thursday, and citing people familiar with the submissions. It is almost three times the bank’s net income of 4.3 billion euro for 2011. The improper accounting was enough for the bank to avoid a government bailout, according to the ex-employees.

However, the bank dismissed the complaint, saying “valuations and financial reporting were proper,” Reuters quotes an email from Renee Calabro, a spokeswoman at Deutsche Bank. Calabro claims the allegations have already been investigated by the bank and they have no grounds.

“The allegations of financial misstatements, which are more than two and one-half years old and were publicly reported in June 2011, have been the subject of a careful and thorough investigation, and they are wholly unfounded,” Calabro said in an email.

She said the bank will continue to cooperate with the US Securities and Exchange Commission (SEC) investigation.

Two of the ex-employees allege that the bank misstated the value of insurance provided in 2009 by Omaha, Nebraska-based Berkshire Hathaway Inc. The company is led by billionaire Chairman and Chief Executive Officer Warren Buffett.

Deutsche Bank is already under international scrutiny by US regulators over alleged Libor rate fixing, along with a dozen of other global banks like Citigroup and JPMorgan.

It is notable that one former Deutsche Bank employee, Robert Khuzami, who was the bank's general counsel at the time and is now head of enforcement at the SEC. Khuzami is one of the possible successors to SEC Chairman Mary Schapiro, who is stepping down later this month. Khuzami has already recused himself from other SEC investigations of Deustche Bank, the blog Zero Hedge notes.